Quoting Saraea Banks:" i try to stand up for myself but she freaks out.. then if i say something back my stepdad gets in on it. i'm scared they will kick us out and we have no other family here.."
Then perhaps it's time to go back to New york before taxes? It's very hard to stand up to your parents when you're still in the "I have to do as they say" mindset.. which a lot of teenagers are. And it's harder when you have a loud mouth step-parent that your parent cant stand up to either, but it's time to get a back bone. You're not a child anymore, you have your own child and you're his only voice. Or you can bring it up to your mom when your stepdad isn't around and bring it up in a calm manner.
Like if she does something you don't want done, pull her aside after the event and simply say "I would really appreciate if you didn't do that "and explain why, most people meet you with hostility when they misconstrue how you're coming across to them. I'm not saying you're freaking out, but it could just be a few words that trigger things.